FA-68621 / Toll and parking fee computation / Open access

Prepaid toll account auto-replenishment: the usage-based amount is floored to 500 · case 01

Prepaid toll account auto-replenishment returns a wrong result when the usage-based amount is floored to 500.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Flooring to 500 cents sizes replenishments below a quarter of monthly usage.

VERIFIED REPAIR

Restore the replenish amount rounding rule so that the step reads `-(-x['usage_30d'] // 2000) * 500`.

Unsuccessful approach: Skipping the 500 cent grid charges odd card amounts.

Case contract

Input {balance, charges, threshold, min_replenish, usage_30d, card_ok}. The replenish amount is max(min_replenish, ceil(usage_30d/4) rounded up to a multiple of 500). After each charge, if the balance is strictly below threshold and the card works, one replenishment is added. first_negative is the index of the first charge after which the balance is negative (or null). Return {balance, replenished, first_negative}.

Why this case matters

Fee engines bill customers in integer cents; a wrong boundary, rounding stage or cap scope silently over- or under-charges.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    bal = x['balance']
    n = 0
    first = None
    amt = max(x['min_replenish'], x['usage_30d'] // 2000 * 500)
    for i, c in enumerate(x['charges']):
        bal -= c
        if bal < x['threshold'] and x['card_ok']:
            bal += amt
            n += 1
        if bal < 0 and first is None:
            first = i
    return {'balance': bal, 'replenished': n, 'first_negative': first}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 2574, 'charges': [3000, 650, 650], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 11833, 'card_ok': True}, {'balance': 4274, 'replenished': 2, 'first_negative': None}), ({'balance': 930, 'charges': [3000, 150, 275, 3000, 275, 400, 1200, 650], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 7179, 'card_ok': True}, {'balance': 1980, 'replenished': 5, 'first_negative': 0}), ({'balance': 3406, 'charges': [3000, 650, 400, 400, 3000], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 19012, 'card_ok': False}, {'balance': -4044, 'replenished': 0, 'first_negative': 1}), ({'balance': 288, 'charges': [3000], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 7617, 'card_ok': False}, {'balance': -2712, 'replenished': 0, 'first_negative': 0}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 324, 'charges': [275, 650, 1200, 1200, 400, 650, 1200, 3000], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 11394, 'card_ok': True}, {'balance': 3749, 'replenished': 4, 'first_negative': None}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None})], [({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 2515, 'charges': [400], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 3531, 'card_ok': True}, {'balance': 2115, 'replenished': 0, 'first_negative': None}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 1219, 'charges': [150, 400, 275, 1200, 275, 275], 'threshold': 500, 'min_replenish': 2500, 'usage_30d': 15594, 'card_ok': False}, {'balance': -1356, 'replenished': 0, 'first_negative': 3}), ({'balance': 412, 'charges': [400, 3000, 650], 'threshold': 500, 'min_replenish': 2500, 'usage_30d': 13088, 'card_ok': True}, {'balance': 3362, 'replenished': 2, 'first_negative': None}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 2633, 'charges': [650, 150, 275, 1200, 3000, 150, 400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 12112, 'card_ok': False}, {'balance': -3192, 'replenished': 0, 'first_negative': 4}), ({'balance': 1282, 'charges': [1200, 150, 1200, 150, 3000], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 15237, 'card_ok': True}, {'balance': 3582, 'replenished': 2, 'first_negative': None})], [({'balance': 26, 'charges': [150, 1200, 3000, 400], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 19243, 'card_ok': False}, {'balance': -4724, 'replenished': 0, 'first_negative': 0}), ({'balance': 2453, 'charges': [650, 275], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 7993, 'card_ok': True}, {'balance': 1528, 'replenished': 0, 'first_negative': None}), ({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 1341, 'charges': [400, 3000, 275], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 15381, 'card_ok': True}, {'balance': 1666, 'replenished': 1, 'first_negative': None}), ({'balance': -329, 'charges': [3000, 150, 1200, 400], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 7527, 'card_ok': True}, {'balance': 2421, 'replenished': 3, 'first_negative': 0}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 552, 'charges': [275, 1200], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 7045, 'card_ok': True}, {'balance': 1077, 'replenished': 1, 'first_negative': None}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None})], [({'balance': 2290, 'charges': [1200, 650, 150, 1200, 400, 1200], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 6040, 'card_ok': True}, {'balance': 2490, 'replenished': 2, 'first_negative': None}), ({'balance': 2621, 'charges': [3000, 150, 1200, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 17666, 'card_ok': True}, {'balance': 2621, 'replenished': 1, 'first_negative': None}), ({'balance': 2757, 'charges': [1200, 3000, 150], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 14481, 'card_ok': False}, {'balance': -1593, 'replenished': 0, 'first_negative': 1}), ({'balance': 777, 'charges': [650, 3000, 400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 17628, 'card_ok': True}, {'balance': 1227, 'replenished': 1, 'first_negative': None}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 1586, 'charges': [650, 650, 275, 1200], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 6189, 'card_ok': True}, {'balance': 2811, 'replenished': 2, 'first_negative': None})], [({'balance': 1234, 'charges': [650, 3000, 650, 275], 'threshold': 1000, 'min_replenish': 2000, 'usage_30d': 16752, 'card_ok': False}, {'balance': -3341, 'replenished': 0, 'first_negative': 1}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 767, 'charges': [3000, 275, 275, 400, 3000, 3000, 275], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 18564, 'card_ok': True}, {'balance': 5542, 'replenished': 3, 'first_negative': None}), ({'balance': 3840, 'charges': [275, 275, 1200, 400, 150], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 4963, 'card_ok': True}, {'balance': 1540, 'replenished': 0, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 979, 'charges': [275, 275], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 19904, 'card_ok': True}, {'balance': 5429, 'replenished': 1, 'first_negative': None}), ({'balance': 3921, 'charges': [275, 3000, 275], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 12856, 'card_ok': True}, {'balance': 3871, 'replenished': 1, 'first_negative': None}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None})]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('fee oracle' + ' %d' % i, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fee oracle 0	`{'balance': 2850, 'first_negative': None, 'replenished': 1}`	`{'balance': 3350, 'first_negative': None, 'replenished': 1}`	Failed
fee oracle 1	`{'balance': 3274, 'first_negative': None, 'replenished': 2}`	`{'balance': 4274, 'first_negative': None, 'replenished': 2}`	Failed
fee oracle 2	`{'balance': 1980, 'first_negative': 0, 'replenished': 5}`	`{'balance': 1980, 'first_negative': 0, 'replenished': 5}`	Passed
fee oracle 3	`{'balance': -4044, 'first_negative': 1, 'replenished': 0}`	`{'balance': -4044, 'first_negative': 1, 'replenished': 0}`	Passed
fee oracle 4	`{'balance': -2712, 'first_negative': 0, 'replenished': 0}`	`{'balance': -2712, 'first_negative': 0, 'replenished': 0}`	Passed
fee oracle 5	`{'balance': -525, 'first_negative': 0, 'replenished': 0}`	`{'balance': -525, 'first_negative': 0, 'replenished': 0}`	Passed
fee oracle 6	`{'balance': 1749, 'first_negative': None, 'replenished': 4}`	`{'balance': 3749, 'first_negative': None, 'replenished': 4}`	Failed
fee oracle 7	`{'balance': 0, 'first_negative': None, 'replenished': 0}`	`{'balance': 0, 'first_negative': None, 'replenished': 0}`	Passed

SHA-256 / 64c19f39de5cd1936a34fab2e23b558575196174d93b9769ff8749e45cd7c802

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    bal = x['balance']
    n = 0
    first = None
    amt = max(x['min_replenish'], -(-x['usage_30d'] // 4))
    for i, c in enumerate(x['charges']):
        bal -= c
        if bal < x['threshold'] and x['card_ok']:
            bal += amt
            n += 1
        if bal < 0 and first is None:
            first = i
    return {'balance': bal, 'replenished': n, 'first_negative': first}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 2574, 'charges': [3000, 650, 650], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 11833, 'card_ok': True}, {'balance': 4274, 'replenished': 2, 'first_negative': None}), ({'balance': 930, 'charges': [3000, 150, 275, 3000, 275, 400, 1200, 650], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 7179, 'card_ok': True}, {'balance': 1980, 'replenished': 5, 'first_negative': 0}), ({'balance': 3406, 'charges': [3000, 650, 400, 400, 3000], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 19012, 'card_ok': False}, {'balance': -4044, 'replenished': 0, 'first_negative': 1}), ({'balance': 288, 'charges': [3000], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 7617, 'card_ok': False}, {'balance': -2712, 'replenished': 0, 'first_negative': 0}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 324, 'charges': [275, 650, 1200, 1200, 400, 650, 1200, 3000], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 11394, 'card_ok': True}, {'balance': 3749, 'replenished': 4, 'first_negative': None}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None})], [({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 2515, 'charges': [400], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 3531, 'card_ok': True}, {'balance': 2115, 'replenished': 0, 'first_negative': None}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 1219, 'charges': [150, 400, 275, 1200, 275, 275], 'threshold': 500, 'min_replenish': 2500, 'usage_30d': 15594, 'card_ok': False}, {'balance': -1356, 'replenished': 0, 'first_negative': 3}), ({'balance': 412, 'charges': [400, 3000, 650], 'threshold': 500, 'min_replenish': 2500, 'usage_30d': 13088, 'card_ok': True}, {'balance': 3362, 'replenished': 2, 'first_negative': None}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 2633, 'charges': [650, 150, 275, 1200, 3000, 150, 400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 12112, 'card_ok': False}, {'balance': -3192, 'replenished': 0, 'first_negative': 4}), ({'balance': 1282, 'charges': [1200, 150, 1200, 150, 3000], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 15237, 'card_ok': True}, {'balance': 3582, 'replenished': 2, 'first_negative': None})], [({'balance': 26, 'charges': [150, 1200, 3000, 400], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 19243, 'card_ok': False}, {'balance': -4724, 'replenished': 0, 'first_negative': 0}), ({'balance': 2453, 'charges': [650, 275], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 7993, 'card_ok': True}, {'balance': 1528, 'replenished': 0, 'first_negative': None}), ({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 1341, 'charges': [400, 3000, 275], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 15381, 'card_ok': True}, {'balance': 1666, 'replenished': 1, 'first_negative': None}), ({'balance': -329, 'charges': [3000, 150, 1200, 400], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 7527, 'card_ok': True}, {'balance': 2421, 'replenished': 3, 'first_negative': 0}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 552, 'charges': [275, 1200], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 7045, 'card_ok': True}, {'balance': 1077, 'replenished': 1, 'first_negative': None}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None})], [({'balance': 2290, 'charges': [1200, 650, 150, 1200, 400, 1200], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 6040, 'card_ok': True}, {'balance': 2490, 'replenished': 2, 'first_negative': None}), ({'balance': 2621, 'charges': [3000, 150, 1200, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 17666, 'card_ok': True}, {'balance': 2621, 'replenished': 1, 'first_negative': None}), ({'balance': 2757, 'charges': [1200, 3000, 150], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 14481, 'card_ok': False}, {'balance': -1593, 'replenished': 0, 'first_negative': 1}), ({'balance': 777, 'charges': [650, 3000, 400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 17628, 'card_ok': True}, {'balance': 1227, 'replenished': 1, 'first_negative': None}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 1586, 'charges': [650, 650, 275, 1200], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 6189, 'card_ok': True}, {'balance': 2811, 'replenished': 2, 'first_negative': None})], [({'balance': 1234, 'charges': [650, 3000, 650, 275], 'threshold': 1000, 'min_replenish': 2000, 'usage_30d': 16752, 'card_ok': False}, {'balance': -3341, 'replenished': 0, 'first_negative': 1}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 767, 'charges': [3000, 275, 275, 400, 3000, 3000, 275], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 18564, 'card_ok': True}, {'balance': 5542, 'replenished': 3, 'first_negative': None}), ({'balance': 3840, 'charges': [275, 275, 1200, 400, 150], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 4963, 'card_ok': True}, {'balance': 1540, 'replenished': 0, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 979, 'charges': [275, 275], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 19904, 'card_ok': True}, {'balance': 5429, 'replenished': 1, 'first_negative': None}), ({'balance': 3921, 'charges': [275, 3000, 275], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 12856, 'card_ok': True}, {'balance': 3871, 'replenished': 1, 'first_negative': None}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None})]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('fee oracle' + ' %d' % i, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fee oracle 0	`{'balance': 3100, 'first_negative': None, 'replenished': 1}`	`{'balance': 3350, 'first_negative': None, 'replenished': 1}`	Failed
fee oracle 1	`{'balance': 4192, 'first_negative': None, 'replenished': 2}`	`{'balance': 4274, 'first_negative': None, 'replenished': 2}`	Failed
fee oracle 2	`{'balance': 1980, 'first_negative': 0, 'replenished': 5}`	`{'balance': 1980, 'first_negative': 0, 'replenished': 5}`	Passed
fee oracle 3	`{'balance': -4044, 'first_negative': 1, 'replenished': 0}`	`{'balance': -4044, 'first_negative': 1, 'replenished': 0}`	Passed
fee oracle 4	`{'balance': -2712, 'first_negative': 0, 'replenished': 0}`	`{'balance': -2712, 'first_negative': 0, 'replenished': 0}`	Passed
fee oracle 5	`{'balance': -525, 'first_negative': 0, 'replenished': 0}`	`{'balance': -525, 'first_negative': 0, 'replenished': 0}`	Passed
fee oracle 6	`{'balance': 3145, 'first_negative': None, 'replenished': 4}`	`{'balance': 3749, 'first_negative': None, 'replenished': 4}`	Failed
fee oracle 7	`{'balance': 0, 'first_negative': None, 'replenished': 0}`	`{'balance': 0, 'first_negative': None, 'replenished': 0}`	Passed

SHA-256 / 191d15aae5e70b1f4f02d9410d5d724c02215adcc8475ed78a79e1b8c686a264

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    bal = x['balance']
    n = 0
    first = None
    amt = max(x['min_replenish'], -(-x['usage_30d'] // 2000) * 500)
    for i, c in enumerate(x['charges']):
        bal -= c
        if bal < x['threshold'] and x['card_ok']:
            bal += amt
            n += 1
        if bal < 0 and first is None:
            first = i
    return {'balance': bal, 'replenished': n, 'first_negative': first}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 2574, 'charges': [3000, 650, 650], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 11833, 'card_ok': True}, {'balance': 4274, 'replenished': 2, 'first_negative': None}), ({'balance': 930, 'charges': [3000, 150, 275, 3000, 275, 400, 1200, 650], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 7179, 'card_ok': True}, {'balance': 1980, 'replenished': 5, 'first_negative': 0}), ({'balance': 3406, 'charges': [3000, 650, 400, 400, 3000], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 19012, 'card_ok': False}, {'balance': -4044, 'replenished': 0, 'first_negative': 1}), ({'balance': 288, 'charges': [3000], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 7617, 'card_ok': False}, {'balance': -2712, 'replenished': 0, 'first_negative': 0}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 324, 'charges': [275, 650, 1200, 1200, 400, 650, 1200, 3000], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 11394, 'card_ok': True}, {'balance': 3749, 'replenished': 4, 'first_negative': None}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None})], [({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 2515, 'charges': [400], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 3531, 'card_ok': True}, {'balance': 2115, 'replenished': 0, 'first_negative': None}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 1219, 'charges': [150, 400, 275, 1200, 275, 275], 'threshold': 500, 'min_replenish': 2500, 'usage_30d': 15594, 'card_ok': False}, {'balance': -1356, 'replenished': 0, 'first_negative': 3}), ({'balance': 412, 'charges': [400, 3000, 650], 'threshold': 500, 'min_replenish': 2500, 'usage_30d': 13088, 'card_ok': True}, {'balance': 3362, 'replenished': 2, 'first_negative': None}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 2633, 'charges': [650, 150, 275, 1200, 3000, 150, 400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 12112, 'card_ok': False}, {'balance': -3192, 'replenished': 0, 'first_negative': 4}), ({'balance': 1282, 'charges': [1200, 150, 1200, 150, 3000], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 15237, 'card_ok': True}, {'balance': 3582, 'replenished': 2, 'first_negative': None})], [({'balance': 26, 'charges': [150, 1200, 3000, 400], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 19243, 'card_ok': False}, {'balance': -4724, 'replenished': 0, 'first_negative': 0}), ({'balance': 2453, 'charges': [650, 275], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 7993, 'card_ok': True}, {'balance': 1528, 'replenished': 0, 'first_negative': None}), ({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 1341, 'charges': [400, 3000, 275], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 15381, 'card_ok': True}, {'balance': 1666, 'replenished': 1, 'first_negative': None}), ({'balance': -329, 'charges': [3000, 150, 1200, 400], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 7527, 'card_ok': True}, {'balance': 2421, 'replenished': 3, 'first_negative': 0}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 552, 'charges': [275, 1200], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 7045, 'card_ok': True}, {'balance': 1077, 'replenished': 1, 'first_negative': None}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None})], [({'balance': 2290, 'charges': [1200, 650, 150, 1200, 400, 1200], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 6040, 'card_ok': True}, {'balance': 2490, 'replenished': 2, 'first_negative': None}), ({'balance': 2621, 'charges': [3000, 150, 1200, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 17666, 'card_ok': True}, {'balance': 2621, 'replenished': 1, 'first_negative': None}), ({'balance': 2757, 'charges': [1200, 3000, 150], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 14481, 'card_ok': False}, {'balance': -1593, 'replenished': 0, 'first_negative': 1}), ({'balance': 777, 'charges': [650, 3000, 400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 17628, 'card_ok': True}, {'balance': 1227, 'replenished': 1, 'first_negative': None}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 1586, 'charges': [650, 650, 275, 1200], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 6189, 'card_ok': True}, {'balance': 2811, 'replenished': 2, 'first_negative': None})], [({'balance': 1234, 'charges': [650, 3000, 650, 275], 'threshold': 1000, 'min_replenish': 2000, 'usage_30d': 16752, 'card_ok': False}, {'balance': -3341, 'replenished': 0, 'first_negative': 1}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 767, 'charges': [3000, 275, 275, 400, 3000, 3000, 275], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 18564, 'card_ok': True}, {'balance': 5542, 'replenished': 3, 'first_negative': None}), ({'balance': 3840, 'charges': [275, 275, 1200, 400, 150], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 4963, 'card_ok': True}, {'balance': 1540, 'replenished': 0, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 979, 'charges': [275, 275], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 19904, 'card_ok': True}, {'balance': 5429, 'replenished': 1, 'first_negative': None}), ({'balance': 3921, 'charges': [275, 3000, 275], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 12856, 'card_ok': True}, {'balance': 3871, 'replenished': 1, 'first_negative': None}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None})]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('fee oracle' + ' %d' % i, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fee oracle 0	`{'balance': 3350, 'first_negative': None, 'replenished': 1}`	`{'balance': 3350, 'first_negative': None, 'replenished': 1}`	Passed
fee oracle 1	`{'balance': 4274, 'first_negative': None, 'replenished': 2}`	`{'balance': 4274, 'first_negative': None, 'replenished': 2}`	Passed
fee oracle 2	`{'balance': 1980, 'first_negative': 0, 'replenished': 5}`	`{'balance': 1980, 'first_negative': 0, 'replenished': 5}`	Passed
fee oracle 3	`{'balance': -4044, 'first_negative': 1, 'replenished': 0}`	`{'balance': -4044, 'first_negative': 1, 'replenished': 0}`	Passed
fee oracle 4	`{'balance': -2712, 'first_negative': 0, 'replenished': 0}`	`{'balance': -2712, 'first_negative': 0, 'replenished': 0}`	Passed
fee oracle 5	`{'balance': -525, 'first_negative': 0, 'replenished': 0}`	`{'balance': -525, 'first_negative': 0, 'replenished': 0}`	Passed
fee oracle 6	`{'balance': 3749, 'first_negative': None, 'replenished': 4}`	`{'balance': 3749, 'first_negative': None, 'replenished': 4}`	Passed
fee oracle 7	`{'balance': 0, 'first_negative': None, 'replenished': 0}`	`{'balance': 0, 'first_negative': None, 'replenished': 0}`	Passed

SHA-256 / e21f920734ddf0f6e066bcc3e60458e10ba274422e857e7c4c393caf65b502b9

Verification & scope

A deterministic, bounded toy model with a stipulated contract; it makes no claim of conformance to any agency manual or standard. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:48:03.869083+00:00.

Case digest / 551ff772d7cf2bf73d5a0acc13864a58f153177d7b9e10df67cebf2fd704d1d7